The Vitamin D Workshop Inc. was established in 1974 as a mechanism for organization of academic meetings devoted to the science of vitamin D. Vitamin D exerts biological actions via the vitamin D receptor which is expressed throughout the body. Basic cell and molecular research, epidemiological studies and clinical trials have linked vitamin D to a host of chronic diseases including osteoporosis, cancer, heart disease and obesity. The surge of publications on vitamin D and chronic disease has drawn attention to an individual's vitamin D status and the possibility that vitamin D supplementation may have preventive actions against chronic diseases. Worldwide, government agencies are re-evaluating recommended dietary allowances for vitamin D, and many are considering fortification and regulatory issues. Physicians and other health professionals have received mixed messages concerning when to measure vitamin D status, what the optimal serum vitamin D level is and how to institute supplementation regimens for deficient patients. Collectively these factors warrant an annual meeting of vitamin D scientists to disseminate current findings, discuss the emerging basic and applied research, and bring areas of controversy to light. The Vitamin D Workshop is the only recurring scientific meeting specifically focused on vitamin D. Through keynote lectures, invited speakers, promoted oral communications and poster presentations, the Workshop's broad scope combines state of the art basic research on vitamin D biology for basic scientists with clinical and observational reports geared towards applied scientists, policy makers and health professionals. This R13 application seeks partial support for the 17th-21st Workshops on Vitamin D which will be held annually from 2014- 2018 in the United States and Europe.